The invention relates to a method and an arrangement for monitoring the bearing currents in an electrical machine.
Methods of this type are known, for example, from the international patent application WO 2006/134068. One of the methods described in this document provides for the electrical voltage which is present between a shaft in the electrical machine and the housing to be measured with the aid of electrical contact brushes, which rest mechanically on the shaft and make electrical contact with it. The voltage measured in this way is evaluated in an evaluation device, and a measurement signal is produced when a bearing current occurs.
Furthermore, the cited document discloses another method for monitoring the bearing current; in this other method, a bearing which bears the shaft of the machine is electrically isolated from the machine housing. The electrical voltage between the bearing and the housing is measured, and evaluated, in order to detect a bearing current event.